The present invention relates to prosthetic devices, and more particularly pertains to a prosthetic device for a lower extremity amputee which simulates the movements of the amputee's natural foot and ankle.
Prosthetic devices date from antiquity, and the splinting of limbs has been found in mummies from ancient Egypt. Contemporary medical science has made astounding advances since the days of using a stick having a slab of wood tied to its lower end for serving as a splint.
Modern medical science has designed numerous types of prosthetic devices for below-the-knee amputations. Orthotics is the field of medical science which is specifically related to the fabrication and application of prosthetic devices and combines the fields of biomechanics and physiology in designing such prosthetic devices. "Orthoses" is the term which denotes orthopedic appliances used to correct, support, align, prevent, or improve the function of movable body parts. Orthoses are used for individuals having lower extremity bracing problems; prosthetic devices are used for amputees. One of the most common types of amputation is the Syme amputation which results in the removal of the entire foot. As a consequence of the Syme amputation, the prosthesis must incorporate an artificial foot.
The prior art reveals a number of prosthetic devices for a total foot amputee. U.S. Pat. Nos. 41,033 (Vaughan), 264,812 (Wolf), 961,582 (Bradley et al.), 1,174,127 (Davis et al.), 2,529,968 (Sartin), and 2,570,581 (McIntyre) all disclose artificial legs. However, the severe limitations of the aforementioned prior art are readily apparent upon close reading of the patents. None of the devices are easily adjustable for matching the pitch and angle of the artificial leg with the amputee's natural leg. In addition, none of the above devices has the ability to absorb shock occurring during the various phases of the gait cycle.
Moreover, the above-cited devices do not avoid the phenomenon known as Trendelenburg gait (a method of walking with an artificial leg that necessitates swinging the prosthesis laterally and forward in gait). Also, the above-cited devices do not disclose structural elements or means which would permit the amputee to smoothly and without difficulty stand or walk on an uneven surface or terrain.
Therefore, there is a need for a prosthetic device which accomplishes all of the above-described purposes, and is also lightweight, extremely durable, and, since the distance from the ground surface to the stump varies for each respective amputee, adaptable for each respective amputee who will wear the prosthetic device. In addition, there is a need for a prosthetic device which is adjustable for accommodating the natural growth of that portion of the individual's leg remaining after the amputation.